• As many already know, studying for the physics GRE and getting accepted into a graduate program is not the final hurdle in your physics career.
• There are many issues current physics graduate students face such as studying for their qualifier, deciding upon a field of research, choosing an advisor, being an effective teaching assistant, trying to have a social life, navigating department politics, dealing with stress, utilizing financial aid, etc.

meegal90
Posts: 5
Joined: Wed Jun 06, 2012 3:55 am

.
Last edited by meegal90 on Fri Jun 08, 2012 5:00 am, edited 1 time in total.

microacg
Posts: 60
Joined: Sat Mar 03, 2012 2:06 pm

Have you tried the question yet?

meegal90
Posts: 5
Joined: Wed Jun 06, 2012 3:55 am

.
Last edited by meegal90 on Fri Jun 08, 2012 5:00 am, edited 1 time in total.

bfollinprm
Posts: 1203
Joined: Sat Nov 07, 2009 11:44 am

meegal90 wrote:Is the answer is 3 fold degenerate with nx,ny and nz values 1,1,3 respectively??
No, and, err..no. So the idea of degeneracy is to count the number of possible combinations of quantum numbers that gives the appropriate energy, with the rule that the n's are quantized as integers. So saying that nx = ny = 1, and nz = 3 is the answer isn't right--that could be one of the ways, but certainly not all; if that's allowed, so is nx = nz = 1, and ny = 3.

Also, you're in a 2-D well, so there are only 2 quantum numbers, not 3 (which is fortunate, because otherwise this particular energy state would be impossible). Wikipedia states E = (hk)^2/(8mPi^2), with k^2 = k(dot)k = pi^2/a^2(nx^2+ny^2).http://en.wikipedia.org/wiki/Particle_i ... onal_boxes

So, that should be enough to answer the question, which is really how many ways can you have nx^2 + ny^2 = 25, since everything else is just a constant, the same on both sides, which allows you to cancel.

meegal90
Posts: 5
Joined: Wed Jun 06, 2012 3:55 am

So the answer is two fold degenerate since quantum numbers can take the value nx=3,ny=4 or nx=4,ny=3. Am i right??

kangaroo
Posts: 130
Joined: Fri Jan 13, 2012 5:31 am

meegal90
Posts: 5
Joined: Wed Jun 06, 2012 3:55 am